Salut!
M NaCl=A Na+ A Cl=23+35, 5=58,5 g/mol
58,5 g NaCl...23 g Na...35,5 g Cl
100 g NaCl....x.................. y
x=23 g*100 g/58,5 g=39,31% Na
y=35,5*100/58,5=60,68% Cl
